Silver halide color photographic materials are well known to be subjected to imagewise exposure and color development, thereby allowing aromatic primary amine color developing agents to react with couplers to produce indophenol dyes, indoaniline dyes, indamine dyes, azomethine dyes, phenoxazine dyes, phenazine dyes and dyes similar thereto, thus forming color images.
In general, the quality of these photographic images is not lasting, but deteriorates with time during storage. In particular, for color photographs having images formed of azomethine dyes or indoaniline dyes, exposure to light or storage under high temperature and high humidity for a long period of time generally induces fading or discoloration of the dye images and further discoloration (yellow stains) of white grounds, resulting in deterioration of the images.
Such deterioration of the image quality is a drawback which may be said to be fatal to recording materials. It has been therefore desired to improve the drawback.
Cyan, magenta and yellow dye images are generally used in color photographs. Of these dyes, the magenta dyes are weakest to light. Investigations for improving the fastness of color photographs have therefore been made attaching importance to prevention of light fading of the magenta dyes. Various investigations have made it possible to improve the fastness of the magenta dyes to considerable levels. As a result, fading or discoloration of the yellow dyes or the cyan dyes has become outstanding.
Diacylpiperazine compounds having a specified structure are proposed in JP-A-2-262654 (the term "JP-A" as used herein means an "unexamined published Japanese patent application"). However, the compounds illustratively disclosed therein were insufficient to customers requesting much higher fastness, and particularly it was necessary to further heighten the effect of improving fading due to moisture, namely wet heat fastness. Moreover, many of the diacylpiperazine compounds illustratively disclosed are solid, although they are improved in solubility to high boiling organic solvents compared with the conventional compounds. They were therefore insufficient to use as high boiling organic solvents for dissolving couplers or other additives.